1. Field of the Invention
The present invention relates to an ink jet recording head for use with an ink jet recording system.
2. Description of the Related Art
An ink jet recording head (hereinafter abbreviated as a recording head) has a substrate including at least a plurality of discharge ports through which ink is discharged, flow paths communicating with respective discharge ports, supply holes through which ink is supplied to the flow paths, and energy generating elements for providing discharge energy to the ink in the flow paths. The ink jet recording head further has a support member for supporting the substrate and an ink supply path forming member for supplying ink to the substrate. The substrate is typically made of silicon (Si). The ink supply path forming member is made of, for example, plastics. A flow path forming member for forming the flow paths is made of, for example, a photosensitive resin, particularly a cationically polymerizable resin and a photopolymerization catalyst. The photopolymerization catalyst may include, for example, a photo-acid-generating agent containing fluorine atoms, such as iodinium salts of antimony fluoride, sulfonium salts of antimony fluoride, or sulfonium salts of phosphorus fluoride, from the standpoint of photoreactivity.
U.S. Pat. No. 6,592,202 discloses a recording head provided with a rubber member as a part of an ink flow path between a support member supporting a substrate and a supply path. The rubber member used herein is a crosslinked rubber which is crosslinked by a metal oxide such as ZnO or MgO, for example, a butyl rubber or a halogenated butyl rubber.
In the recording head disclosed in this publication, a flow path forming member may contain fluorine atoms caused by a photo-acid-generating agent and an ink supply path forming member or the rubber member may contain metal. For example, the ink supply path forming member may contain a filler component including divalent metal for improvement of its strength and heat resistance or a resin modifier containing bivalent metal for improvement of moldability of resin. In addition, in many cases, the ink supply path forming member uses a butyl rubber or a halogenated butyl rubber having high gas barrier property, or alternatively, bivalent metal salts as a crosslinking agent of a butyl rubber. In addition, in many cases, the rubber member is mixed with a filler containing bivalent metal so as to adjust its strength and cut down costs by reducing its resin component.
In such a case, it may be contemplated that a small quantity of metal as a crosslinking component contained in the ink supply path forming member or the rubber member is eluted into ink. It is believed that this metal reacts with fluorine supplied from the flow path forming member to produce a precipitate. Such a precipitate may cause discharge fault by clogging the discharge ports or staying near the discharge ports.